Curtis Bellofram Pump* for Long-Term Use in Extracorporeal Blood Circuits

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IN recent models of pumps1–5 used for extracorporeal blood circuits, the degree of damage to the blood has been reduced considerably. However, the hemolysis, as an indicator of this damage, may become severe when these pumps are used in long-term perfusions.6 Such long-term perfusions are expected to become useful in treating patients who at present have hopeless, acute coronary infarction and other forms of myocardial failure. This report describes a new pump that embodies the principle of rolling diaphragms; it combines the advantages of a reciprocating pump with the satisfactory blood-handling properties of a membrane type of device.

Description of the Pump

The design is basically that of a piston type of pump (Fig. 1 and Table 1). A Bellofram rolling diaphragm made of Silastic with a dacron mesh reinforcement serves as the seal between the piston and the considerably larger cylinder. The valves (V) are tricuspid semilunar, or flat rubber, or ball valves. The diaphragm is tightly fixed between a retaining plate (R) and the piston body (P). The piston rod (P1), which has a central thread, forms the nut to fix to the retaining plate. The diaphragm runs down the piston skirt, forms a 180-degree convolution, and covers the whole cylinder wall of the blood chamber. It is held in place by the bead (G) that fits into a corresponding groove in a flange on the cylinder (C). When the bead is compressed between the flange of the cylinder and the top part (T) by means of. . .



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